The present invention relates to a method and apparatus for automatically dividing a primary stream of tobacco leaves into a plurality of secondary streams, each containing a predetermined percentage of the primary stream. As used herein, the term "tobacco leaves" includes leaf pieces as well as whole leaves.
Tobacco leaves are initially received by the tobacco processor from the tobacco auction or an intermediate storage facility in bales or bundles. The processor, after removing the leaves from the bale or bundle, separates the leaves from each other, and cuts or tears the tobacco leaf lamina from the tobacco stem. During this processing, it is frequently necessary to divide an initial stream of tobacco leaves, normally carried from one processing area to another on a conveyor, into two or more streams which are directed to separate processing units. For example, tobacco leaves carried on a conveyor are divided into a plurality of streams that are directed into the inlets of tobacco threshers.
Because of the different sizes of individual tobacco leaves, their physical state, and the fact that leaves overlap and are entangled when initially received, accurate division of a stream of tobacco leaves, or tobacco leaf pieces, into multiple streams containing predetermined percentages of the initial stream is not possible with most devices used to separate streams of other materials.
A method and apparatus which has been found to be reasonably effective for this purpose is described in U.S. Pat. No. 2,785,683 to Davidson. In that apparatus, a spiked roller or doffer is positioned to intersect a stream of falling tobacco leaves discharged from the end of a conveyor belt. The outwardly moving spikes on the roller engage a portion of the tobacco leaves, tearing it away from the main stream, thus dividing the initial stream into two streams of tobacco leaves.
When the doffer is moved further inwardly, a larger percentage of the primary leaf stream is contacted, resulting in a greater percentage of the main stream being diverted. Conversely, movement of the doffer further out of the main stream results in the removal of a smaller percentage of the main stream. Thus, the operator is able to control the relative percentages of tobacco leaves in the two streams by adjusting the position of the doffer within the initial stream.
Heretofore, the operator has effected this adjustment by manually taming a spindle connected to the doffer support with a wrench, with the amount of adjustment being based upon the operator's visual assessment of the percentages or ratio of tobacco within the two streams, or by reading of measurements affected by the varying amount of tobacco, e.g., meters measuring the amperage drawn by thresher motors.
This manual adjustment procedure is often difficult and inconvenient due to location of the doffer. More importantly, the procedure does not result in accurate division of the stream into the desired percentages since the operator's visual assessment is frequently inaccurate, because conditions such as the amount of tobacco in the primary stream fluctuates rapidly, and also because the operator may fail to make changes when indicated. A method and apparatus permitting automatic and accurate control of the doffer position within a falling tobacco stream, and thus the control of the percentages of tobacco within the resultant tobacco streams, would be of great utility.
Accordingly, it is the primary aspect of the present invention to provide a method and apparatus for dividing a primary stream of tobacco leaves into a plurality of secondary streams of tobacco leaves by positioning one or more doffers at least partially within the tobacco stream, and automatically controlling the position of the doffer or doffers in response to the ratio of tobacco in the secondary streams, so that the actual ratio of tobacco in the streams equals a predetermined ratio.
Another aspect of the present invention is to provide a method and apparatus for separating a single stream of tobacco into a plurality of streams of substantially equal volume which are fed to threshing units.
Other aspects of the present invention will be apparent to one skilled in the art upon a reading of the following Summary of The Invention and the Detailed Description of The Preferred Embodiment.